Fix build check script

Fix an issue where grep exited with exit code 1 when no lines matched
the final pattern.  Not matching any lines is the expected behavior, but
the variable should be populated with empty string instead of causing
the shell to exit (because of `set -e`).

In addition, do not install dev dependencies since they are not needed

.github/workflows/build-check.sh

@@ -17,10 +17,10 @@ changes=$(
 	grep -v "^ M docs/sitemap\.xml$" |
 	# the following two are specific to GitHub Actions
 	grep -v "^.. output\.log$" |
-	grep -vi "^.. Docker"
+	grep -vi "^.. Docker" || true # force grep to exit 0, even if no lines match
 )
 
-if [[ -n "$changes" ]]; then
+if [ -n "$changes" ]; then
 	echo "\e[31mYou forgot to commit changes to the docs dir!\e[0m"
 	echo 'On your local run \e[33mcomposer build\e[0m then \e[33mgit add\e[0m your changes to the docs dir'
 	echo 'Then \e[33mgit commit --amend\e[0m and \e[33mgit push --force\e[0m'

.github/workflows/build-check.yml

@@ -24,6 +24,7 @@ jobs:
             -   name: Install dependencies
                 uses: php-actions/composer@v6
                 with:
+                    dev: no
                     php_version: 8.3
 
             -   name: Check for uncommitted files